Urban Water Security Research Alliance Urban Creeks in SEQ - can - - PowerPoint PPT Presentation

Urban Creeks in SEQ

• can bugs live anywhere?

Role of habitat and hydrology Fran Sheldon

Stormwater Harvesting and Ecohydrology

Science Forum, 19-20 June 2012

Urban Water Security Research Alliance

CONCEPTUAL MODEL

Urbanisation

Changed hydrology

(magnitude, frequency & duration)

Water Quality Habitat Availability & Quality Invertebrate Diversity & Assemblage Composition

OUTLINE

• Spatial analysis
• Temporal analysis –

preliminary results

• Where to from now?

Large number of sites over many streams Increasing %TIA Tingalpa Creek (forested) Tributary to Blunder Creek (WSUD) Stable Swamp Creek (urban)

SPATIAL ANALYSIS: EXPLORING ACROSS THE %TIA GRADIENT

• Sites distributed

across the %TIA gradient

• Classified as:

– Directly Connected (DC) – black triangles – Not Directly Connected (NDC) –

• pen diamonds

METHODS

Quantitative collections

• Quantitative samples collected from 16

sites across 12 different streams in May 2010

• Modified suction sampler used to collect

samples by placing it over a defined bed area at 3 locations (individual riffles, or runs if riffles were not present) at each site. Semi-Quantitative collections

• 15 of the same sites as 2010

during baseflow conditions

• both spring and autumn of 2007

& 2008

• 250-μm-mesh dipnet used to

collect benthic fauna from a total length of 10 m of habitat along the water’s edge,

• Sampling and sorting followed

EHMP protocols

Richness EPT Taxa %TIA DO (mg/L) DC directly connected to stormwater drainage NDC - not directly connected

RELATIONSHIPS BETWEEN MACROINVERTEBRATE DIVERSITY AND ENVIRONMENTAL VARIABLES

INFLUENCE OF %TIA ON INDIVIDUAL TAXA

Threshold Indicator Taxa Analysis (TITAN) of macroinvertebrate assemblage response to the %TIA gradient May 2010 2007-2008

SPATIAL CONCLUSIONS

• In the directly connected streams (DC), richness, relative

richness and relative abundance of EPT taxa along with 2 macroinvertebrate sensitivity scores (SIGNAL2 and SPEARpesticides), were low when compared with streams without direct connection (NDC).

• Results suggest urban streams in SEQ show similar

responses to urban streams elsewhere – low richness of EPT and other sensitive taxa with increasing % of upstream impervious surfaces

Leigh, C., Dunlop, J.E. and Sheldon, F. (in press). Generalist assemblages in urban streams lack association with the environmental conditions prevailing in their aquatic habitat during baseflow. Freshwater Science. Accepted May 2012.

WHAT DRIVES LOW DIVERSITY

Urbanisation

Changed hydrology

(magnitude, frequency & duration)

Water Quality Habitat Availability & Quality Reduced EPT and Sensitive Taxa Diversity Increased rate of rise and fall Increased magnitude Increased frequency Reduced baseflows Reduced DO under low flow Increased turbidity pH and Salinity Pesticides and Heavy metals Increased nutrients Increased siltation in pools Reduced habitat diversity in riffles (infilling by sand) Incised channels and lower habitat complexity

METHODS

• Sites:

– Tingalpa Creek (reference) – Stable Swamp Creek – Sunnybank, Keats Rd (urban) – Tributary to Blunder Creek – Daintree Close (WSUD)

• Sampling

– 3 ‘sites’ within each ‘reach’ – Replicate samples from specific habitats (riffles, pools, snags, macrophytes) – Macroinvertebrates – 250m sweep 10m of habitat – Logged water quality and hydrology – Sampled every 6 weeks June 2011 – March 2012

SITES

Tingalpa Creek (reference) Tributary to Blunder Creek, Daintree Close (WSUD) Stable Swamp Creek – Sunnybank, Keats Rd (urban)

5 10 15 20 25 30 35 Blunder Tributary Stable Swamp Tingapla Macrophyte/Snag Pool Riffle

Richness (S)

SPECIES RICHNESS

WSUD Urban Forested Mean Richness ± SE

ASSEMBLAGE DIFFERENCES: JUNE 2011

Axis 1

• 2

2 4

Axis 2

• 1.0

0.0 1.0 Blunder Creek Macrophyte Blunder Creek Pool Blunder Creek Riffle Stable Swamp Macrophyte Stable Swamp Pool Stable Swamp Riffle Tingalpa Pool Tingalpa Riffle Tingalpa Snag

2D Stress: 0.09

Blunder Creek All habitats Stable Swamp Pool habitats

WSUD Urban Forested

Stable Swamp Riffle habitats Tingalpa Riffle habitats

Multidimensional Scaling (MDS) Plot, Pray-Curtis Similarity

RELATIVE ASSEMBLAGE SIMILARITIES IN WINTER

Forested Riffles Urban Riffles Urban Pools

Urban riffles more similar in assemblage composition to forested riffles than urban pools

IF FLOW IS DRIVING REDUCED DIVERSITY EXPECT SHIFTS IN URBAN RIFFLE ASSEMBLAGES OVER SUMMER

Forested Riffles Urban Riffles Urban Pools

Winter Summer

IF HABITAT IS DRIVING REDUCED DIVERSITY EXPECT NO CHANGE IN URBAN RIFFLE ASSEMBLAGES OVER SUMMER

Forested Riffles Urban Riffles Urban Pools

Winter Summer

HABITAT MAPPING

SUMMARY

• Riffle sites in urban streams more diverse that originally

thought

• Pool sites in urban streams extremely low diversity
• If there were fewer riffles present in urban streams,

compared with forested, then apparent low diversity could reflect reduced habitat availability

• But, habitat availability appears to be similar

– Habitat quality may differ

• Next stage of study

– Complete temporal analysis of assemblage change – Relate to water quality and hydrology data – Map riffle habitat “quality” across the %TIA gradient

ACKNOWLEDGEMENTS

• Spatial Sampling

– Jason Dunlop (DERM) – 2007-2008 collections – Catherine Leigh (ARI) – 2010 collections

• Temporal Sampling Research Team

– Michael Newham – Wendy Neilan – Carolyn Poulson – Janine Woods – Lars Pelzer

Urban Water Security Research Alliance THANK YOU www.urbanwateralliance.org.au